Assessing the utility and feasibility of immune function assays to understand Smallmouth bass (Micropterus dolomieu) health in the Chesapeake Bay watershed

Abstract

Skin lesions and mortality events of both adult and young smallmouth bass have occurred in the Chesapeake Bay, an area largely influenced by agriculture and heavily impacted by various toxic contaminants. Co-infections of bacterial, viral and parasite pathogens have been documented in both adult and young fish suggesting immunosuppression. To better understand the risk factors associated with these fish health issues, functional immune assays were developed. Adult bass were collected from two sites with different land use (forested versus agricultural). At both sites some level of immunosuppression was noted when compared to laboratory-reared bass. Histopathology of the wild bass indicated the presence of parasites and various inflammatory lesions. These results indicate immune function assays may add important information to fish health assessments, however, need to be used in conjunction with other lines of evidence to help inform managers on relationships among land use, contaminants and wild fish health.